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Biomedical subjects

M S Dahn

Publications and source records attributed to M S Dahn.

43 records · Page 3Linked to original sources
PubMed1983

Cardiovascular performance and myocardial infarction following aortic surgery.

A review of all patients who had undergone aortic reconstruction for aortoiliac occlusive disease and aneurysm over the previous five years demonstrated that fatal myocardial infarctions occurred most frequently two or three days remote from surgery. The most outstanding hemodynamic finding was sustained tachycardia which displayed a maximum risk on the second postoperative day. The peak coincided with the period of maximum incidence of fatal myocardial infarction. We suggest that the degree of postoperative tachycardia, which is a major determinant of myocardial oxygen consumption, contributes significantly to the risk of acute myocardial ischemia.

Acidosis↗
PubMed1982

Hormonal changes and their influence on metabolism and nutrition in the critically ill.

This is a brief review of the observed hormonal alterations following trauma and sepsis. The major changes noted in the metabolic status of the stressed patient have been characterized by deranged carbohydrate metabolism, altered metabolic rate as measured by oxygen consumption and increased ureagenesis. Each of these phenomena are regulated to a large extent by the specific hormonal profile of the patient. Failure of insulin and growth hormone production have been associated with glucose intolerance, excessive urinary nitrogen loss and a fatal outcome. Glucagon, cortisol and catecholamines exhibit sustained elevation and have been associated with increased metabolic rate and excessive ureagenesis. These changes are usually self limited following trauma but will persist if the patient enters a septic phase. The use of specific nutritional support, namely hypertonic glucose versus a balanced fat emulsion system in the face of sepsis is considered.

Animals↗
PubMed1979

Negative inotropic effect of albumin resuscitation for shock.

The inotropic effects of albumin were studied in 94 seriously injured patients who received an average of 14.5 transfusions, 9.2 liters of crystalloid and 0.9 liters of plasma prior to end of operation; 46 patients, by random selection, received added albumin averaging 31 gm during operation, 198 gm during the early postoperative period of extravascular fluid sequestration, and 395 gm during the first 4 days of the later fluid mobilization period. Left ventricular stroke work index (LVSWI) was plotted against pulmonary wedge pressure (Ppw) in 22 patients who had indwelling thermistor pulmonary artery catheters at the time of the first study. Calculated heart work units (WU) were derived from the pulse pressure, mean arterial pressure, pulse rate, and central venous pressure (CVP) in patients without LVSWI measurements. Albumin supplementation increased serum albumin (4.2 vs. 2.9 gm%), plasma volume, CVP (15 vs. 9 cm H2O), but did not alter red cell volume (1,531 vs. 1,519 ml). The ratio of LVSWI/Ppw fell in albumin patients (1.9 +/- 1.6 vs. 4.8 +/- 1.8), and the ratio of WU/CVP was significantly depressed in albumin patients (4.9 +/- 2.3 vs. 7.3 +/- 2.1). The slopes of the LVSWI/Ppw and WU/CVP were shifted to the right in albumin patients. This negative inotropic effect was associated with impaired oxygenation, as reflected by an increased ratio of inspired oxygen per arterial oxygen tension (0.62 +/- 0.06 vs. 0.33 +/- 0.1). Finally, 24 of the 46 albumin-treated patients were digitalized for heart failure, compared to only 11 of the 48 nonalbumin patients. Pending subsequent studies, albumin should be considered a potentially negative inotropic agent.

Albumins↗
PubMedDate not supplied

Alterations in the metabolism of exogenous lipid associated with sepsis.

The responses to an exogenous lipid challenge of nonhypermetabolic surgical patients requiring parenteral nutrition and seriously ill septic patients were compared. All patients received a 500-ml intravenous infusion of a 10% lipid emulsion over a 4-hr period. An early elevation of glycerol and triglyceride was noted during the infusion suggesting chylomicron fractionation. Peak triglyceride levels were higher in the septic group but the rate of lipid clearance appeared essentially identical in both septic and nonseptic patients. Lipoprotein lipase levels remained constant and were equal for both groups. Significant late ketone body production was statistically identical in both groups despite depressed albumin levels in the septic group suggesting adequate hepatic ketogenic capacity in septic as well as nonseptic patients.

Adult↗
PubMedDate not supplied

Altered immunologic function and nitrogen metabolism associated with depression of plasma growth hormone.

The specific role of endogenous growth hormone in regulating nitrogen metabolism during surgical stress and infection remains unclear. We have studied splanchnic amino acid uptake and plasma concentrations in patient groups exhibiting growth hormone hypersecretion or relative growth hormone depression in response to stress. Splanchnic amino acid uptake was similar in both groups although plasma levels were significantly higher in the presence of depressed growth hormone production suggesting increased net peripheral proteolysis. In association with this latter observation. T lymphocyte subset analysis revealed a greater incidence of depressed helper to suppressor cell ratios in the presence of depressed growth hormone suggesting a greater impairment of cellular immunity.

Aged↗
PubMedDate not supplied

Endocrine mediators of metabolism associated with injury and sepsis.

We have studied the endocrine characteristics of 13 seriously ill patients with the use of a provocative intravenous glucose bolus. Notable in this stressed patient population was that no major interpatient differences in response to glucose were found for insulin, glucagon, cortisol, or epinephrine. However, following glucose challenge half of this group (7/13) exhibited a prominent "paradoxical" mean human growth hormone (hGH) elevation (26.4 +/- 9.3 microU/ml) whereas the others (6/13) exhibited only a minor increase (7.8 +/- 2.9 microU/ml). In addition, norepinephrine levels were significantly higher in the latter group suggesting that the adrenergic nervous system plays a major role in regulating hGH in stress.

Aged↗